December 18, 2009

Updated at 12:00 PM: Epic and historic snowstorm to bury Mid-Atlantic...glancing blow will still be significant for Southern New England

A bundle of deep tropical moisture is lifting north out of the Gulf of Mexico and about to encounter deep cold air draped across the Eastern Seaboard. This will result in an historic East Coast storm that will drop three feet of snow in some of the mountains of Western Virginia, Maryland and Northern West Virginia. Metropolitan areas of DC, Baltimore, Philadelphia and most of the Interstate 95 corridor will see up to two feet of snow. Blizzard conditions will occur on the western side of the storm, perhaps as far inland as Washington DC, but more likely from Long Island through New Jersey into Delaware and Eastern Maryland later Saturday. Snow moves into New England later Saturday afternoon to Saturday evening from south to north, and tapers by Sunday midday with this fast-moving storm. Accumulation map is included in this video - one thing to add, though...just after this broadcast I added the February 10-12, 1983 reference onto the snow map. I did this because this storm has such a similar look, and in that storm Southern New England recorded 10"-20" of snow. While I'm not currently forecasting that with this storm, I want to at least acknowledge that if the similarities continue, higher amounts will occur.

**Noon update: New guidance is in. Good agreement with the forecast. All looks good for now. Important to note that while I've labeled only the 6-12 and 2-4 areas, that does not mean you're one or the other. For instance, the MA Turnpike should see somewhere just over half a foot. Please interpolate for your location between the 2"-4" zone for the NH/MA border (and coast of ME) and the 12" expected along the South Coast. Overall, currently I'd expect either side of 3" extreme Southern NH, 7" MA Pike, 12" Central CT/RI/SE MA, 15" South Coast. Blizzard conditions possible very late Saturday night and Sunday morning from Long Island to Cape Cod...